Field of the Invention
The present invention relates to a working medium for absorption refrigerators, and an absorption refrigerator using this medium.
Description of Related Art
A working medium used generally in conventional absorption refrigerators is a lithium-bromide/water system. Water is a cooling medium, and lithium bromide is an absorbing liquid. Accordingly, the water which is the cooling medium is frozen in an evaporator for generating a cold energy, the evaporator constituting the absorption refrigerator. It is therefore difficult that temperature of a heat medium for transporting the cold energy is adjusted to a temperature below a freezing point of water in the absorption refrigerator having an ordinary specification.
International Publication WO 2004/087830 (Patent Literature 1) discloses an absorption refrigerator in which a cold energy corresponding to the freezing point or lower is obtained by using a lithium-bromide/water system working medium including 1,4-dioxane as an additive which is a boiling-point-lowering-type organic substance having an azeotropic point with water.
From the viewpoint of prevention of corrosion of parts formed of a stainless steel used for the apparatus, Japanese Patent Application Laid-Open No. Hei 11-080978 (Patent Literature 2) discloses an aqueous solution composition for an absorption heat pump that contains lithium bromide as a main component, and a molybdate and an alkali hydroxide as inhibitors, the concentration of the alkali hydroxide being restricted.
“Kurita Industrial Chemicals Handbook”, edited by Kurita Water Industries chemicals Handbook Editorial Committee (Non Patent Literature 1) describes aminotrimethylenephosphonic acid which is of a phosphonic acid type and is widely used as a corrosion inhibitor for cooling-water systems.